Hi Guys, I know you already answered lots of questions about it.
But I read a lot, and does not matter if I increase samples, lightening, resolution to 100%, clamps, reinstall blender, it renders super quick (like 10 seconds) and with no quality, and ridiculously grainy.
I even realize that if samples is on 2 or 10.000 it does not matter, it renders the same way.
I could not find an answer to my problem, what should I do?
Thank you!
Sharing the .blend file will make it easier for others to help you with this.
There are two settings, one is the Preview, which is the mode you are currently using, and the other is Render.
Set the Render samples to at least 64, and try rendering again using the Render button.
*jpg compression 
also bottom of layers panel
set Denoise
should help get a very clear render
happy cl
in the image above it’s the renderresult in the Image-editor with 1000 samples, i think it must be something different…
One place to check is the sample count for each render layer. It can override your scene sample count and it seems that you might have it set to something else than zero.
You’re right, I didn’t notice the icon.
Probably it’s your system or graphic driver. Which system are you on? It’s better you share the file, or at least a stripped-down version of it.
check System preferences
you have engine set to use GPU (but grayed out) means it’s using CPU (it should be)…
also which Blender, system specs… ?
Best is to simply share your scene file - issue would be solved by now without a guessing game 
HI I am a new user, that means I cannot share the blender file, I tried twice, but he website does no allow me,
Render layers are set to 3
samples are already set to 1k, and it renders on the same speed as 0 samples. It does not matter the number i put there.
Yes I am clicking on render button to render to have the final result, in fact I was rendering an short animation and I saw the low quality images and stopped it.
How should I share the file with you, is there any other option?
I also tried to change the engine GPU and CPU and I do not have different results =(
You cannot even use s.t. like google drive and then share the link here?
When i get home I will try 
Hi Rebecca, I’ve increased your user level so you should now be able to share .blend files.
Clock.blend (1.0 MB)
Clock.blend1 (1.0 MB)
Hi, thank you all for the help, I am uploading the blender file. I was not sure which one was the correct, so I uploaded both.
I checked the samples under render layer on scene tab. It was not zero
Under Sampling on the rendering tab, find Layer Samples, click the drop-down box, and choose ignore. I got it to render out at 1000 samples then.
Alternately, you could hop over to the Render Layers tab, and set your samples there.
The file with the “1” is the backup file, depending on the setting on User Preferences | File | Save Versions, it may have different numbers, it’s an older version of the file you’ve saved.
It worked!
I changed the samples in layer and clicked on ignore drop down box on Layer samples
Thank you all. I appreciate everyone’s help.
I only had time to go back to it now. i am sorry for the super late answer
